The present invention relates to the general field of cooling the moving blades of a turbomachine, and in particular the blades of the high pressure turbine.
It is known to provide the moving blades of a turbomachine gas turbine, such as the high and low pressure turbines, with internal cooling circuits enabling them to withstand without damage the very high temperatures to which they are subjected while the turbomachine is in operation. Thus, in a high pressure turbine, the temperature of the gas coming from the combustion chamber can reach values well above those that the moving blades of the turbine can withstand without damage, thereby having the consequence of limiting their lifetime.
By using such cooling circuits, air which is generally introduced into the blade via its root, passes through the blade following a path formed by cavities made inside it, prior to being ejected via orifices opening out in the surface of the blade.
Numerous different embodiments of such cooling circuits are in existence. Thus, certain circuits make use of cooling cavities that occupy the entire width of the blade, thus presenting the drawback of limiting the thermal effectiveness of the cooling. In order to mitigate that drawback, other circuits, such as those described in patent documents EP 1 288 438 and EP 1 288 439 propose using edge cooling cavities occupying only one of the sides (pressure side or suction side) of the blade, or both sides, together with a large central cavity between said edge cavities. Although such circuits are effective from a thermal point of view, they remain difficult and expensive to make by molding and the weight of the resulting blade is large.